As a fabric separable fastener member, there has been widely used a separable fastener member in which a hook or loop fastening element (hereinafter sometimes simply referred to as a fastening element) is risen from a surface of a woven or knitted base fabric. In usual, such a fabric separable fastener member is, in view of strength, elasticity, or a recovering property from deformation, produced mainly by weaving or knitting a polyamide or polyester fiber as the fiber for the base fabric and for the fastening element. In the case where the fiber constituting the fastening element is not appropriately anchored to the base fabric, the fabric separable fastener member cannot exploit a desired property.
In order to dissolve the above problem, in practical cases, the fabric separable fastener member is provided with an adhesive layer (or back-coated layer) on the surface where the fastening element does not rise, i.e., on the backside (back surface) of the separable fastener member, to anchor the base fabric fiber and the fastening element fiber together. The adhesive layer (or back-coated layer) is producible from a variety of adhesive agents called a back-coating agent, and is typically a urethane layer.
However, the conventional separable fastener member provided with the adhesive layer has a drawback that the fastener member deteriorates in hand touchiness because of inflexibility thereof. Further, deterioration of the adhesive agent caused by usage such as washing or ironing gradually decreases anchoring ability (fixability) of fibers, resulting in degradation of the engaging function of the fastener member.
Moreover, the fabric separable fastener member is often dyed in a desired color for usage depending on application. However, in the fabric separable fastener member on which a conventional polyurethane back-coating agent is applied, due to hard dyeing property of the polyurethane, even if a disperse dye is used for dyeing, the separable fastener member is low in the color fastness and releases the dyestuff to stain other fiber products. Accordingly, there has been widely produced a separable fastener member which is fabricated by dyeing only a polyamide or polyester fiber which takes a dye well, subsequently applying a polyurethane back-coating agent to the dyed fiber to form a polyurethane layer without dyeing the polyurethane layer. However, such a production process takes many or long steps for obtaining a separable fastener member having a desired color, and low in productivity (efficiency in product supply). Consequently, a separable fastener member without the adhesive layer is proposed.
For example, Japanese Patent Application Laid Open No. 250434/1989 (JP-01-250434) (Patent document 1) discloses a sheet material for a separable fastener, which comprises a backing material partially containing a bonding yarn and a pile yarn knitted into the backing material. In the sheet material, the bonding yarn comprises a thermoplastic binding material having a low melting point and fuses to anchor fibers (yarns) with each other. In the document, the bonding yarn includes a combined filament yarn in which a multifilament yarn made of a high-melting component and a monofilament yarn made of a low-melting component are doubled, or a sheath-core structure conjugated fiber which comprises a low-melting component as a sheath component. More concretely, as the bonding yarn, there is used a doubling and twisting yarn comprising a polyamide or polyester monofilament having a low melting point and a polyamide or polyester multifilament having a high melting point, or a yarn comprising a high-melting polyester multifilament and a low-melting ethylene-vinyl acetate copolymer surrounding around or filling inside of the multifilament. Moreover, as the pile yarn, there is used a mono- or multifilament made of a polyamide 66, a monofilament made of a polypropylene.
Moreover, Japanese Patent Application Laid Open No. 115312/1993 (JP-05-115312) (Patent document 2) discloses a fabric separable fastener member comprising a ground part (a base fabric) comprising a sheath-core structure conjugated fiber, in which the conjugated fiber comprises a low-melting polymer as the sheath component and the low melting polymer of the conjugated fiber fuses and anchors the fibers together. The document describes that the sheath-core structure conjugated fiber includes a conjugated fiber which comprises a low-melting polyester copolymer as the sheath component, and a high-melting polyester or polyamide 6 as the core component. Further, as the pile yarn, a polyamide 6 filament is concretely employed, and a loop part (element) of the separable fastener member is formed by raising the pile yarn.
However, in these separable fastener members, although the bonding fibers (binder fibers) fuse and anchor the pile fibers forming a fastening element of the separable fastener member in a certain degree, anchoring (fixation) of the pile fibers to the base fabric fibers is insufficient, and the separable fastener member cannot resist to usage for a long period.    Patent document 1: JP-01-250434 (Claims 1 and 2, and Examples)    Patent document 2: JP-05-115312 (Claim 1 and Examples)